Safety paper and method of making the same



Patented Jan. 5, 1932 UNITED STATES PATENT OFFICE ARTHUR E. REMICK, OF ROCHESTER, NEW YORK, ASSIGNOR TO THE TODD COMPANY,

INC., OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK 4 SAFETY PAPER AND METHOD OF MAKING THE SAME No Drawing.

This invention relates to a safety paper for making bank checks, drafts, bonds and other value representing instruments, and more particularly to the variety of such paper com- 'prising a chemical ingredient havlng the characteristic of reactionwith the ink eradlcating substances in general use, to produce a conspicuous discoloration, or stain, indicative of an attempted erasure, to serve as a warn- 19 ing that an effort has been made to alter the instrument.

The chief object of the invention is to provide a more practicable and eflicient paper of this character capable of being inexpensively manufactured in the desired commercial forms. More particularly stated, it is an object of the invention to provide such a paper which will be quickly and conspicuously altered in color by the application of the comac mon eradicators, to, produce a substantially indelible and striking indication of changes made in the subject matter of the instrument, as aprotection against fraud. A further object is to provide a simple, practical and economical method of manufacturing safety paper having the advantages set forth.

To these and other ends, the invention resides in certain improvements and combinations of parts, all of which will be more fully described, the novel features being pointed out in the claims at the end of this specification.

Safety papers have heretofore been made to include sensitive chemical ingredients, but such ingredients have generally proven more or less ineffective as a protection because of insufficient reaction, particularly as regards conspicuous change in color when treated with the common eradicators, or some of have been open to one or another of the above objections. I have discovered a group of organic substances, the use of which has demonstrated their peculiar fitness for the purposes of this invention, namely, the substances Application filed August 22, 1929.

them, or because of the impermanence of such' Serial No. 387,820.

known as diphenyl guanidine, triphenyl guanidine, and their substitution products such as ortho or para di-tolyl guani-dine and ortho or para anisyl guanidine, and analogues, homologues and derivatives. These substances having .the essential characteristics of diphenyl guanidine may be described as guanidine substances and are intended to be included by such description in the appended claims as within the spirit and scope of this invention.

These substances are normally solids, reacting with oxidizing agents, such as sodium hypocholorites, to yield relatively insoluble precipitates of sharply conspicuous color, generally a deep purple brown. It is pre ferred, however, toemploy a salt of these substances, as, for example, the acetate, as the salts are soluble in water and hence more easily applied to the paper, and their precipitates on the paper are more insoluble and indelible.

The substances described are characterized by a relatively high degree of permanence against the effect of atmospheric or light conditions for long periods of time and they react quickly and sharply with the eradicators in'general use to produce a deep and conspicuous stain of an insoluble and permanent character not afiected by the application of excessive amounts of bleach.

A further advantage of these substances is that they are colorless, or substantially so, depending largely upon their state of purity, so that they are particularly advantageous for addition to paper of white or any other desired natural or imparted color, without sensibly altering such color, until treated with I an eradicator when a deep, conspicuous and substantially indelible stain is at once produced to give warning that the paper has been tampered with.

The application of these substances to the paper is a relatively simple matter requiring no special skill. They may be incorporated in the paper at any convenient stage of its I manufacture, being added, for example, to the pulp, or to the web, or with the sizing, and as a solution, or suspension, or in the 100 solid state. The base may be dissolved in suitable solvents and applied to the paper.

The method preferred at the present time is to impregnate the paper with one of the above su stances by passing the paper in the web through a three percent aqueous solution of its acetate, and subsequently dry the paper by methods well understood in the art. The described substances are thus capable of application to the paper in an economical manner by known and practical methods. The amount to be used will vary, of course, with the intensity of reaction desired, the character of the paper, and other conditions, as will be readily understood in the art. By Way of example, it has been found in practice that when added to the pulp in the beater, thirty pounds of the base is generally sufficient for treatment of a ton of pulp.

The invention thus provides a safety paper havin to a marked degree the desired qualities 0 adaptability and eflicienoy for its intended use, and which is capable of being produced by known and practicable methods at a comparatively low cost, as well as a method of making such paper having similar advantages.

While certain substances and methods have been referred to herein by name and specifically described, it is to be understood that other closely related substances within the general class described may be employed with equal advantage and that the above described method may be modified in various details, as well understood by those skilled in this art, without departing from the spirit of the invention.

I claim:

1. A safety paper for making bank checks and other value representing instruments, to which is added a guanidine substance.

2. A safety paper for making bank checks and other value representing instruments, to which is added a salt of a guanidine substance.

3. A safety paper for making bank checks and other value representing instruments, to which is added the acetate of a guanidine substance.

ink eradicator.

ARTHUR E. REMICK.

4. The method of making safety paper comprising the addition thereto as an m-' gredient of a salt of a guanidine substance.

6. The method of makin safety paper comprising the step of adding thereto the r acetate of a guanidine substance.

7. A'safety paper for making bank checks and other value representing instruments containing a salt of diphenyl guanidine adapted to react with chemical eradicating means to develop a conspicuous color change.

a 8.. A method of making safety paper comrising the step of adding to the paper either uring or after the manufacture thereof a 

